US2447307A - Electrode holder - Google Patents

Description

Aug. 17, 1948. `w. F. BAKER ErrAL IELEC'IRODE` HOLDER Filed Nov. 2e, 194el Patented Aug. 17, 1948 ELECTRODE HOLDER William Frank Baker and Ian Jack Pickering,

Birmingham, England, assignors to The General Electric Company, Limited, London, England Application November 26, 1946, Serial No.` 712,435

In Great Britain October 23, 1944 Section 1, Public Law 690, August 8, 1946 Patent expires October 23, 1964 (Cl. 21S- 8) 3 Claims. 1

This invention relates to Welding electrode holders and in particular to electrode holders of the kind embodying means for gripping and releasing the electrodes, switch means for interrupting the path of the welding current, and external control means for operating the electrode gripping and releasing means and the switch means at the will of the operator.

In accordance with the present invention, an improved electrode holder of the kind indicated above is provided having control means common to both the electrode gripping means and the switch means and adapted to operate the switch to interrupt the current circuit to de-energise an electrode before operating the gripping means to release the electrode from the holder.

One embodiment of the invention is illustrated by way of example in the single figure of the accompanying drawing which shows a complete holder in sectional side elevation.

Referring now to the drawing, the holder comprises a tubular body I of moulded insulating material to one end of which is attached an electrode carrying head 2 formed a block of metal e. g. copper having a stopped axial bore 3 and screw connected to the body I through a coupling member 4. If desired, the head 2 may 'be of anodised aluminum alloy so as to prevent accumulation of electrode spatter on the head and partially to insulate the head.

A transverse hole 5 is provided in the end of the head 2 for the passage of the end of an electrode rod 6 the rod being gripped in the holder by the pressure of the notched end of a copper plunger 'I arranged to slide axially but without rotation in the bore 3 in the head 2 under the urge of a compression spring 8 surrounding the plunger and disposed between a fixed abutment formed by the end of coupling member 4 and a collar 9 on the plunger.

The plunger I extends into the holder body I, being preferably surrounded by an air space IIJ to reduce heat transfer to the holder body, and at its rear end is iixedly attached a conducting extension II adapted to slide on an insulating seating I2 in the holder body I, and this extension I I forms or bears one of the four contacts of a single pole double break switch the contact surfaces of which are in the case illustrated disposed in two planes parallel to the axis of the holder I. Another contact I3 is mounted in xed position in the holder body, spaced and insulated from but in the same plane as the contact I I and to this iixed contact I3 is attached the end 0I the current supply lead (not shown) 2 introduced into the holder body I through the end thereof away from the head 2.

The movable switch element is formed by a metal bridge piece I4 having contact surfaces I5 at each end. The cof-operating contact surfaces of the switch may be of curved e. g. part cylindrical form the axes of curvature of the contact surfaces of each pair being disposed at right angles to one another. The bridge piece I4 is arranged to make sliding movements without rotation on a fixed guide pin I6 mounted in the holder I between the two contacts II and I3 and extending vertically through the plane containing contacts I I and I3 and across the space within the holder I. On the outer side of the bridge piece I4 is mounted a thimble I'I of insulating material extending through a hole in the wall of the holder I and a compression spring I8 surrounds the guide pin I6 tending to urge the bridge piece IA and contacts I5 away from cantacts II and i 3 and to cause the thimble I'I to project outside the holder body I.

A lever I9 having a yoked end 20 is pivotally mounted on the outside of the holder body I, for movement towards and away from the body about a pivot pin 2| located in the holder body between the head 2 and the switch II, I3, I4 the body of the lever I9 engaging the thimble I1.

The limbs of the yoke end 20 of the lever I9 are shaped as shown at 22 and engage at their rear sides with the ends of a transverse pin 23 fixed in the end of the plunger 'I and extending through slots in the wall of the holder body I.

The parts are shown in the position where an electrode rod 6 is gripped between the end of plunger I and the side of the hole 5 in the electrode carrying head 2, and the switch is in the open position. By taking a grip on the holder body I the lever I9' may be moved towards the holder body I and the thimble I1 and switch bridge piece I4 depressed to close the current circuit to the electrode with pressure, the limbs of the yoke end 2B meantime moving away from the ends Of the pin 23. Upon release of the grip, the lever is returned by the spring I8 to the stable open circuit position shown. By swinging the same lever I9 outwards from the position shown, i. e. in the direction of arrow A, the limbs of the yoke end 2i) are caused to engage pin 23 to draw the plunger 'I rearwardly or to the right in the drawing, against spring 8 to release the grip on the end of the electrode 6 and permit adjustment or replacement thereof.

It will readily be seen therefore that with a holder as described above, both the operation Qf I9, and the arrangement is such that release of the electrodesfrom .the holder cannot be `eiieoted without rst opening switch II, I3, I4 to break the current circuit and thereby de-energising the electrode.

'Ihe plunger 'I may be provided with a detachable nose 24 screwed to the main part of ,the plunger, to permit replacement ofthe part vmost liable to deterioration without sacrice vof `the entire plunger l.

It is not necessary that a single `lever I9 should control both switching and electrode gripping. rlhus, two separate levers may be employed operating through a transmission member common to both switching and electrode gripping, one lever being operated by the fingers to open and close the switch and the other by the thumb to control electrode gripping.

`We claim: f

1. A welding-`electrode holder comprising a body, normally closed electrode gripping means, '.normally'open switch contacts electrically connected in` the 'energizing circuit for said gripping means,- -meansf'to mount said switch contacts for movement toward and away fromv one another, an external membenwmeans to mount said mein- Iber for movement relative to said-body, said mem- --ber r`occupying a certain `normal position with respect to said body, means yoperatively connect- .ing said electrode gripping means and said -Inem- 'benand means operatively connecting said switch contacts l'and Asaid member, said member rendering said first named means operative to release an'electrode'when moved in one direction relative to said body awayfrom normal 'position and said member rendering said second named means effective to close said switch contacts when said member is moved in an oppositedirection relative to said body away from normal position.

2. A welding electrode holder comprising a body, a conducting plunger slidable in said body, l a spring normally biasing said plunger in a direction to clamp an electrode, switch contacts disposed in said body and in the current circuitto .said plunger, saidswtch contacts normally being open, contact'operating means extending through said body, and an external lever pivotally mounted on said body, means to mount said lever for rotation about its pivot from a normal position in one direction to close said contacts and in the other 'direction to move said plunger against said spring.

3. A welding electrode holder as set forth in claim 2, wherein the switch contacts form a double break in the current circuit.

WILLIAM FRANK BAKER. IAN JACK PICKERING.

REFERENCES CITED The following references are oi record in the Elle of this patent:

UNITED STATES PATENTS-

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